#! /usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright (c) JoinQuant Development Team
# Author: Huayong Kuang <kuanghuayong@joinquant.com>

class A(object): pass


class B(A): pass


class C(B): pass


class D(A): pass


assert isinstance(A(), A)
assert isinstance(B(), A)
assert isinstance(C(), A)
assert isinstance(D(), A)
